A Corporate pilot attempted to deviate from a DEN TRACON vector to avoid a building microburst but because of traffic was vectored through it and encountered severe turbulence.

Narrative

[I] departed BJC. After takeoff I was given a 030 degree heading and to maintain 8;000 FT; I observed a swirling mass of dirt at ground level. The dirt that was picked up was getting increasingly thicker; larger in diameter and then started to increase in altitude. I requested 10 degrees to the right and was advised to make the request from the next Controller. I made the request and received the deviation. The column of dirt increased above my aircraft altitude. I requested another 10 degrees to the right with no response from Approach. I entered severe turbulence causing the aircraft to go above and below 8;000 FT. The Controller answered my earlier call at which time I advised I was turning right as I observed dirt on the ground being picked up spreading outward from a large area down draft. I advised the Controller I was in severe turbulence. The Controller advised me to turn immediately to 030 and advised of traffic; then issued a traffic alert; and I advised of visual contact with the traffic advising the Controller he was turning me into a microburst. Controller didn't care. I drove the aircraft through terrible turbulence with three passengers.